Whereas Scout is influenced by discrimination at school, how does society influence Jem in Harper Lee's To Kill a Mockingbird?

In Harper Lee's To Kill a Mockingbird, society's racism and social injustice most influence Jem in a very negative way.

While witnessing Tom Robinson's trial, Jem was well aware that all evidence revealed in the trial pointed to Robinson's innocence, not his guilt. The most critical point of evidence is that Mayella Ewell was bruised on the right side of her face, something only a left-handed man facing her was capable of doing. Evidence in court revealed that Robinson has been crippled in his left arm and hand since childhood; he is so crippled that he is unable to keep his left hand on the Bible long enough to take the oath as he is being sworn into the witness stand. In contrast, Bob Ewell proves to be left-handed and testifies to being ambidextrous. Due to all of the evidence, Jem is convinced his father will win the case and is absolutely devastated when the jury returns with a guilty verdict, because he knows they have made their verdict not based on evidence but based on racism. He is so devastated that he cries and says, "It ain't right," repeatedly on the way home after the trial (Ch. 22).

The day after the trial, Jem confides to Miss Maudie just how much the jury's decision altered his perception of Maycomb's people:

It's like bein' a caterpillar in a cocoon, that's what it is ... . Like somethin' asleep wrapped up in a warm place. I always thought Maycomb folks were the best folks in the world, least that's what they seemed like. (Ch. 22)

His statement helps us see that whereas Jem once saw Maycomb's people as good, decent folks, he now sees them as essentially evil due to the social injustice they have inflicted on Robinson out of racist hatred.

During their conversation, Miss Maudie helps him see that more of Maycomb's people tried to help Robinson than Jem has realized, including the African Americans, Judge Taylor, and Sheriff Heck Tate. Miss Maudie's words of wisdom help but not sufficiently. By the end of the novel, Jem's anger towards social injustice manifests in physical violence, whereas at the start of the novel, Jem had a much calmer temper than Scout. For example, Jem acts violently when Scout brings up the hypocritical behavior of her third-grade teacher. Scout describes his violent behavior in the following narration:

Jem was suddenly furious. He leaped off the bed, grabbed me by the collar and shook me. (Ch. 26)

He further shouts that he never wants to hear another word about the trial.

Jem's violent behavior shows us just how much Jem has been influenced in terms of being hurt and angered by society's injustices and racist hatred.